FEMALE REPRODUCTION Unlike males, who

are able to produce sperm cells throughout their reproductive lives, females produce a finite number of egg cells.

During early fetal development germ cells migrate into the ovaries and differentiate into oogonia

OOGONIA

The oogonia divide by mitosis for the next few months and some differentiate into primary oocytes.

By fifth month there are about 7 million primary oocytes, but most will degenerate during the next 2 months

OOGONIA Those that remain will

be surrounded by a single layer of squamous epithelial cells (follicle cells) called a primordial follicle.

Degeneration of primary oocytes continues.

At birth =1million primordial follicles

At puberty 400,000 remain

Only 400-500 will reach maturity

OVARIAN CYCLE Monthly changes that

occur in the ovary during a woman’s reproductive life.

Each month FSH stimulates primordial follicles to grow and mature (follicular phase)

Ovulation- release of the egg (LH)

Luteal phase the corpus luteum produces progesterone that maintains uterine walls

If fertilization does not occur, the corpus luteum degenerates, within 2 weeks into a mass of scar tissue called the corpus albicans

GROSS ANATOMY The ovaries are solid,

ovoid structures, about 2 cm in length and 1 cm in width.

Like the testes, they develop from embryonic tissue along the posterior abdominal wall, near the kidneys.

Accessory organs include the uterine tubes, uterus, and vagina.

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UTERINE TUBES (FALLOPIAN TUBES)

Receive the ovulated oocyte and provide a site for fertilization

Empty into the superolateral region of the uterus via the isthmus

Expand distally around the ovary forming the ampulla

The ampulla ends in the funnel-shaped, ciliated infundibulum containing fingerlike projections called fimbriae

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UTERINE TUBES (FALLOPIAN TUBES)

Function: events occurring in the uterine tube

Fimbriae sweep oocyte into tube, cilia & peristalsis move it along, sperm reaches oocyte in ampulla, fertilization occurs within 24 hours after ovulation & zygote reaches uterus about 7 days after ovulation

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FALLOPIAN TUBE HISTOLOGY

Cilia sweep egg/zygote toward the uterus

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UTERUS

Hollow, thick-walled organ located in the pelvis anterior to the rectum and posterosuperior to the bladder

Body: Major portion of the uterus Fundus: Rounded region superior to the

entrance of the uterine tubes Isthmus: Narrowed region between the body

and cervix

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UTERUS

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UTERINE HISTOLOGY

Endometrium Simple columnar epithelium Stroma of connective tissue and endometrial glands

Stratum functionalis: Shed during menstruation

Stratum basalis: Replaces stratum functionalis each month

Myometrium 3 layers of smooth muscle

Perimetrium Visceral peritoneum

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UTERINE HISTOLOGY

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ENDOMETRIUM

Simple columnar epithelium

Endometrial glands

ENDOMETRIUM Proliferative phase:

glands and blood vessels scattered throughout the functional zone with little or no branching.

New glands form and endometrium thickens.

Secretory phase: glands are enlarged and have branches. Preparing the endometrium for implantation

If no implantation then endometrium breaks down and menstruation begins.

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FEMALE: LATERAL VIEW

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CERVIX

Narrow lower neck of the uterus which projects into the vagina inferiorly

Cervical canal – cavity of the cervix that communicates with: The vagina via the external os The uterine body via the internal os

Cervical glands secrete mucus that covers the external os and blocks sperm entry except during midcycle

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Fornix

Endocervical canal

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VAGINA

Thin-walled tube lying between the bladder and the rectum, extending from the cervix to the exterior of the body

Wall consists of three coats: fibroelastic adventitia, smooth muscle muscularis, and a stratified squamous mucosa

Mucosa near the vaginal orifice forms an incomplete partition called the hymen

Vaginal fornix: upper end of the vagina surrounding the cervix

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FEMALE EXTERNAL GENITALIA

Mons pubis: fatty pad over the pubic symphysis Labia majora & minora: folds of skin encircling

vestibule where find urethral and vaginal openings

Clitoris: small mass of erectile tissue Bulb of vestibule: masses of erectile tissue just

deep to the labia on either side of the vaginal orifice

Perineum: Area between the vagina and anus

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FEMALE EXTERNAL GENITALIA

Perineum

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BARTHOLIN’S GLANDS

(AKA: VESTIBULAR GLANDS) The Bartholin's glands are located on each side

of the vaginal opening. They secrete fluid that

helps lubricate the vagina. Sometimes the ducts of

these glands become obstructed. Fluid backs up into the gland

and causes swelling (Bartholin's cyst)

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MAMMARY GLANDS

Modified sweat glands that produce milk (lactation) Amount of adipose determines size of breast Milk-secreting glands open by lactiferous ducts at

the nipple Areola is pigmented area around nipple Suspensory ligaments suspend breast from deep

fascia of pectoral muscles (aging & Cooper’s droop) Mammary line is a thickened ridge of embryonic

tiwwue that extends from the axilla to the groin.

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BREAST

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BREAST

Prolactin from the pituitary gland stimulates the synthesis of milk

Oxytocin from the posterior pituitary gland stimulates milk ejection

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LYMPHATIC DRAINAGE

Lymph nodes draining the breast are located in the axilla.

OOGENESIS: BEFORE BIRTH

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During fetal development, oogonia (stem cells) divide by mitosis to make primary oocytes

Primary oocytes begin meiosis and stop in prophase I until puberty Primordial follicles:

Support cells that surround the oocyte in the ovary

2 million present at birth

400,000 remain at puberty

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OOGENESIS: AFTER PUBERTY

Each month, hormones cause several follicles to develop, which triggers the primary oocyte to resume meiosis I

Polar bodies: When the cell divides, all the cytoplasm and organelles stay with one of the new cells, the other cell is just DNA, and is called a polar body and is discarded

Secondary oocyte: The stage at which ovulation occurs.

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OOGENESIS: AFTER PUBERTY

The secondary oocyte begins meiosis II, but stops in metaphase II

The secondary oocyte is ovulated Meiosis II is completed only if it is fertilized.

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OOGENESIS

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LIFE HISTORY OF OOGONIA

As a fetus, oogonia divide to produce millions by mitosis but most degenerate (atresia)

Some develop into primary oocytes & stop in prophase stage of meiosis I200,000 to 2 million present at birth40,000 remain at puberty but only 400 mature

during a woman’s life Each month, hormones cause meiosis I to

resume in several follicles so that meiosis II is reached by ovulation

Penetration by the sperm causes the final stages of meiosis to occur

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OVARIES

Each follicle consists of an immature egg called an oocyte

Cells around the oocyte are called: Follicle cells (one cell layer thick)

Stimulated to mature by FSH from the pituitary gland Granulosa cells (when more than one layer is

present) Thecal cells: Cells in the ovarian stroma

Thecal & granulosa cells work together to produce estrogen

A protective layer of glycoprotein forms around the egg called the zona pellucida

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FOLLICLE DEVELOPMENT

1. Primordial follicle: one layer of squamous-like follicle cells surrounds the oocyte

2. Primary follicle: two or more layers of cuboidal granulosa cells enclose the oocyte

3. Secondary follicle: has a fluid-filled space between granulosa cells that coalesces to form a central antrum

4. Graafian follicle: secondary follicle at its most mature stage that bulges from the surface of the ovary

5. Corpus luteum : ruptured follicle after ovulation

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OVARY HISTOLOGY

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OVARY HISTOLOGY

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Zona pellucida

1° Oocyte(arrested in prophase I)

Granulosa cells

Thecal cells

Nucleus

Primordial follicle

Primary Follicle

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SECONDARY FOLLICLEFluid-filled antrum

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GRAAFIAN FOLLICLE

Fluid filled antrum

Granulosa cells

Oocyte 2°

Corona radiata

Stalk

Zona pellucida

CORPUS LUTEUM

After ovulation, the remains of the follicle are transformed into a structure called the corpus luteum.

If a pregnancy occurs, it produces progesterone to maintain the wall of the uterus during the early period of development.

CORPUS ALBICANS

If fertilization does not occur, the corpus luteum will begin to break down about 2 weeks after ovulation.

Degeneration occurs when fibroblasts enter the corpus luteum and a clump of scar tissue forms called the corpus albicans.

OVARIAN AND UTERINE CYCLES